The invention relates generally to gas turbine engines, and more particularly to a system and method for monitoring the efficiency of a turbine engine.
Modern gas turbines may be monitored to ensure efficient operation. One manner of monitoring the gas turbines may include arranging an ensemble of thermocouples (TCs), typically metallic measurement instruments, around the exhaust annulus of a gas turbine to monitor the temperature of the gas-phase products leaving the engine. Typically, the absolute and relative temperatures measures by these TCs may be fed into a digital control system (DCS) to regulate the air intake and fuel flow rate of the gas turbine so as to increase the overall performance of the engine.
Due to their size and discrete placement, the TCs are limited in their ability to make an accurate estimate of the average temperature in the exhaust. Attempts to overcome this shortcoming have included adding more TC's into the exhaust annulus. However, as more TCs are added to the exhaust annulus, the pressure drop across the metal instrumentation rakes in the exhaust grows. This may lead to increased back pressure on the engine, which may deleteriously alter performance. Accordingly, there is a need for techniques and systems that may accurately monitor and adjust the efficiency and performance of a gas turbine engine, while minimizing the back pressure induced to the engine via the monitoring equipment.